1. Field of the Invention
This invention is directed to a mechanism to control the advance of a film strip in a film strip projector.
2. Description of the Prior Art
Film strip projectors are well known. There are many patents in existence directed to their optics and to their general structure. Film strip projectors utilize strips of film which have sprocket holes along at least one edge and have spaced scenes or frames along the length thereof. The projectors are arranged so that, when one of the framed scenes is properly positioned with respect to the projector optics, the scene is projected. The projector optics usually include a cropping or framing mask which edgewise limits the illumination of the film strip to the framed size of the scene on the film strip so that only a scene is projected, and not extraneous information.
It is convenient to engage the sprocket holes on the film strip to advance the strip from one scene to another. This can be simply accomplished by means of a manual knob connected to drive a sprocket wheel due to film engagement. However, such a simple drive mechanism does not provide for advance to the predetermined position where the next scene on the film strip is properly aligned with respect to the mask in the projector.
A projector and a film strip advance mechanism are taught in P. J. Kilday U.S. Pat. No. 3,003,393 and others cited therein, the entire disclosure of which is incorporated herein by this reference. The present invention is an improvement over the Kilday disclosure, in that the present invention is directed to an improved, more trouble-free and economic mechanism. In accordance with the present film strip advance mechanism, the film strip is quickly and accurately advanced to a new film strip position, with convenient ease of framing.